Electric heating unit



N v- 1 3 L. A. SOMERO ELECTRIC HEATING UNIT Fild July 15, 1965 Leonard A. Some '0 INVENTOR.

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. sealed chamber of a for the transmission of United States Patent 3,353,003 ELECTRIC HEATING UNIT Leonard A. Somero, Box 259A, New Ipswich, NH. 03071 Filed .Iuly-IS, 1965, Ser. No. 472,190 8 Claims. (Cl. 219-341) ABSTRACT 0F THE DISCLOSURE An electric heating unit including an annular housing having radial fins to which heat is conducted from a fluid heating medium within the housing surrounding an inner tube sealed at opposite ends by dielectric supports projecting from end covers closing the axial ends of the housing. Electrically conductive rods are supported Within the the tube by means of spaced insulating supports. A plurality of heating elements extend unsupported between the rods in parallel circuit arrangement. One of the end covers mount both a thermal switch which extends into the fluid heating medium and the terminals for the rods.

This invention relates generally to heating units and more specifically to an electrical resistance heating unit comprising an improvement on US. patent application Ser. No. 403,524 filed Oct. 13, 1964.

It is an object of the instant invention to provide an electric heating unit of the type utilizing electrical resistance wires for converting electrical energy to heat energy and whichincludes novel and unique features providing such heat energy to the surrounding atmosphere.

To summarize, the present invention provides a novel housing structure for parallel mounted electric resistance heating elements whereby the heat generated is rendered "available for use insuring the even distribution of heat energy to the surrounding area.

In accordance with the invention an electrical heating unit is mounted in a heat conductive housing utilizes parallel mounted heating elements maintained in heat exchange relationship with fluid heat transmission means contained within the housing to insure even distribution of heat into the housing.

The electric heating unit may be constructed from readily available materials in various shapes or configurations thereby adapting the unit for use when saving space is a major consideration.

An important feature of the present invention is to provide an electric heating unit utilizing parallel mounted resistance wires wherein the heating elements are enclosed in an air tight evacuated chamber surrounded by a fluid heat transmission chamber, both of which are contained in a housing upon the exterior of which are secured an assembly of heat radiating fins.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a vertical sectional view of a first preferred form of the electric heating unit comprising the present invention;

'FIGURE 2 is a vertical sectional View taken substantially on the plane of the line 2-2 of FIGURE 1;

FIGURE 3 is a vertical sectional View similar to that of FIGURE 2 of a second preferred form of the present invention; and

FIGURE 4 is a partial vertical sectional view similar to that of FIGURE 2 of another preferred form of the present invention.

Referring now to the drawings and specifically to FIG- URE 1, numeral It) refers generally to the electric heating unit of the present invention. The electric heating unit 10 may be of any desired length, and in the embodiment disclosed in FIGURES 1 and 2 comprises an annular housing 12 in the form of a cylinder having an outer peripheral wall 14, an inner wall 16 and a pair of end walls 18 and 20. These Walls form, in this embodiment of the invention, an annular shaped chamber 22. The walls 14, 16, 13 and 20 are secured together in a wellknown fiuid-tight manner thereby constituting the chamher a fluid sealed chamber. The housing 12 is preferably constructed of any metallic, good heat conducting and radiating material such as iron or steel or the like. Contained within the fluid chamber 22 is the fluid generally designated as 24. In order to insert the fluid 24 into the chamber 22, there is provided a fluid inlet port 26. The inlet port 26 comprises an upstanding, generally circular extension 28 of Wall 14 which is internally threaded and may be closed by threaded inlet cap 30. The purpose and nature of the fluid will be described below.

It will be appreciated, of course, that the inner wall 16 of housing 12 defines a central chamber 32. In the chamber 32 is mounted an inner housing 34 comprising a generally tubular member which is tightly spaced against the inner wall 16. Thus, as may be seen from FIGURES l and 2, the wall 16 is in peripheral encircling engage ment with the inner housing 34. The inner housing 34 defines an inner chamber 35 which is closed by the end members 38 and 40. The end members 38 and 40 comprise dielectric or insulating material, and are sealingly engaged in the end openings of the chamber 36. Supported between the dielectric members 38 and 40 are a pair of conductor rods 42 and 44, which may be of any material which readily conducts electric current such as copper rods. Mounted on the exterior face and extending through the dielectric members 40 are a pair of electric terminals 46 and 43 to which electric conductors 50 and 52 are connected to form part of an electric circuit from any suitable source, not shown. Mounted within the chamber 36 are a plurality of spaced insulating blocks 54, through which the conductor rods 42 and 44 pass for support within the chamber 36. A plurality of electric heating elements 56 are connected across the conductor rods 42 and 44, and are equally spaced therealong Within the chamber 36. It will be appreciated that the heating elements 56 may be of any conventional variety in that each heating element 56 will generate heat energy when electric current is passing through conductor rods 42 and 44.

The chamber 36, by virtue of the sealing engagement of dielectric members 38 and 40 may be evacuated of air. Thus, the chamber 36 will be subjected to a high vacuum or Will be filled with an inert gas to reduce the oxidation of the heating elements or filaments 56 during the passage of electric current therethrough. Thus, it is apparent that the inner housing 34, in view of the plurality of electrically connected filaments 56 mounted therein constitutes a heat generating source for the electric heating unit 1%. The spacing of the filaments 56 along the conductor rods 42 and 44 provides an even distribution of heat energy Within the chamber 36. Further, the use of filaments 56 in a vacuum or inert gas environment enables the filaments to get hotter while at the same time gives them an extended life span.

The fluid chamber 22 which extends completely about the inner housing 34 constitutes a heat conducting or transmitting chamber for transmission of the heat energy generated by filaments 56 to the atmosphere. The fluid 24 contained within the chamber 22 may be any fluid which will readily transmit heat energy, such as water,

alcohol or a water-alcohol mixture. The transfer of heat energy from inner housing 34 to the fluid body 24 is,

enhanced by the surrounding or overlying relationship of inner wall 16 to housing 34. Thus, heat will be conducted through housing 34 to wall 16 to the fluid body 24 which is in communication with the wall 16 throughout the length thereof. Thus, it will be appreciated that the energy generated by the filaments 56 will be transmitted to the outer wall 14 of housing 12 throughout its length quite equally, due to the substantially equal heating of fluid body 24 which is in contact with the outer wall 14.

Secured upon the outer wall 14 of housing 12 are a set of heat radiating fins generally designated at 58. As shown in FIGURES 1 and 2, the fins may conveniently be of a rectangular configuration thereby serving as a means to support the heater unit. However, it will be appreciated that any desired shape or configuration of fins may be employed, it being their major function to provide a means for dissipating the heat delivered by the fluid 24 to outer wall 14, for a useful purpose. The fins 58 may be mounted on the Wall 14 in any conventional manner, as for example by being Welded thereon. Of course, the fins 58 as well as the housing 12 and inner housing 34 are all constructed of a good heat conducting material.

Referring further to FIGURES 1 and 2, a fluid temperature control switch 60 is provided, thereby employing a thermostatic control for the heating unit. The temperature responsive switch 60 is well-known in the art, and includes preset temperature responsive means for controlling the flow of electric current therethrough. The control switch 60 is mounted on the end wall 18 of housing 12 so as to be in communication with the fluid body 24 therein. Extending through the wall 18 are a pair of electric terminals 62 and 64 which are, of course, connected to the control switch 60. The terminal 62 is adapted to be connected to an electric conductor 66 which, along with conductor 50 comprises the energizing circuit for the heating unit. The terminal 64 is connected to terminal 48 by conductor 52, and the control switch 60 is thereby connected in series with the filaments 56. Thus, when the temperature of the fluid body 24 reaches a predetermined level, the control switch 60 will break the electric circuit to the filaments 56, and when the temperature of the fluid 24 falls to a predetermined level, the control switch 60 will close the electric circuit to the filaments 56, thus maintaining the temperature of the fluid body within predetermined limits.

Also provided in end wall 18 is a venting port 68 closed by a bleeder or venting cap 70. The port 68 and cap 70 are provided to control excess pressure within the chamber 22, such as if the fluid therein were to boil and expand in the form of steam, while at the same time retaining the fluid 24 in the chamber. It will be noted also, that the fluid 24 is only filled in the chamber to the level 72, thereby. providing an expansion area within the chamber for the fluid.

Thus, it will be appreciated, that by virtue of the fluid chamber 22 encasing the heating filament 56, the fluid body 24 in the chamber will be heated, thus retaining the generated heat for a relatively long period of time, and along with the control switch 60 allowing the filaments 56 to be energized less often than in conventional heaters. This provides for an appreciably extended period of usefulness for the filaments 56 and the heating unit.

Referring now to FIGURE 3, a second preferred form of the invention is illustrated. In this embodiment, the basic concept of the invention is retained; however, the cylindrical housing 12 is replaced by a rectagular housing or water jacket 112. The rectangular housing 112 has fins 158 mounted thereon, the fins 158 being similar to the fin assembly described in conjunction with the embodiment of FIGURES l and 2. An inner housing 134, also of rectangular cross-section is provided, to house the heat generating elements of the heating unit. A pair of conductor rods 142 and 144 are mounted therein by dielectric members similar to those described above. A plurality of heating filaments 156 are connected across the conductor rods 142 and 144. The outer housing 112 and inner housing 134 define a heat transmission chamber 122 therebetween, which chamber is filled with heat transmitting fluid body 124, similar to fluid body 24 described above. The chamber 122 is, of course, a fluid-tight chamber, and includes a fluid inlet port and venting port such as described above. Further, the inner housing 134 is air-tight and will either have a vacuum or an inert gas environment maintained therein.

Referring now to FIGURE 4, a third preferred embodiment of the present invention is illustrated. In this embodiment, the outer housing 212 is square in configuration and includes heat radiating fins 258 mounted thereon. There is also provided an inner housing 234 in which are maintained in spaced relation a pair of conductor rods 242 and 244 and heating filaments 256 similar to those described above. A heat transmitting fluid body 224 is maintained in the chamber 222 formed between the outer housing 212 and inner housing 234. It will be apparent that this embodiment of the invention is substantially similar to those described above, and further, due to the compact construction will result in a substantial saving of space.

It will be appreciated that the heating units of this invention may be of any length, this factor being governed by the available space in which the heating units are to be placed. Further, these heating units may be of any power output or wattage depending upon the use to be made thereof. Further, the thermostatic control 60 may be utilized with any of the above described embodiments of the invention, or if preferred, may be eliminated,

as the heating fluid will transfer the generated heat evenly to the outer housing thereby providing an extremely efficient means for transferring generated heat to the surrounding area.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. An electric heating unit comprising an axially elongated annular housing having heat radiating fins extending radially therefrom between opposite axial ends, end covers secured to the annular housing closing the axial ends thereof, dielectric end supports projecting .in axial alignment from said end covers spaced radially inwardly of said annular housing, an inner tubular member supported on said end supports in heat conductive relation to the annular housing enclosing a gas-tight chamber, a plurality of insulative support elements mounted in axial spaced relation within the inner tubular member, a pair of spaced electrically conductive rods extending through said support elements within the gas-tight chamber between the end supports, heating elements connected to said rods between. the support elements in a parallel circuit arrangement, a fluid heating medium disposed within the annular housing to a level above the inner tubular member, and a thermal sensing device mounted on one of said end covers projecting into the annular housing below the inner tubular member.

2. The combination of claim 1 including vent means mounted on said one of the end covers in fluid communication With the annular housing above the inner tubular member and a filling inlet mounted on the housing above the level of the fluid heating medium therein.

3. The combination of claim 2 wherein said end supports are cylindrical projections coaxial with the annular housing. v

4. The combination of claim 3 wherein said heating elements extend unsupported transversely across the gastight chamber between the rods to which the heating elements are electrically connected.

5. The combination of claim 1 wherein said end supports are cylindrical projections coaxial with the annular housing.

6. The combination of claim 5 wherein said heating elements extend unsupported transversely across the gastight chamber between the rods to which the heating elements are electrically connected.

7. The combination of claim 1 wherein said heating elements extend unsupported transversely across the gastight chamber between the rods to which the heating elements are electrically connected.

8. The combination of claim 7 including vent means mounted on said one of the end covers in fluid communication with the annular housing above the inner tubular member and a filling inlet mounted on the housing above the level of the fluid heating medium therein.

References Cited FOREIGN PATENTS 3/1948 France. 12/ 1931 Great Britain.

ANTHONY BARTIS, Primary Examiner. 

1. AN ELECTRIC HEATING UNIT COMPRISING AN AXIALLY ELONGATED ANNULAR HOUSING HAVING HEAT RADIATING FINS EXTENDING RADIALLY THEREFROM BETWEEN OPPOSITE AXIAL ENDS, END COVERS SECURED TO THE ANNULAR HOUSING CLOSING THE AXIAL END THEREOF, DIELECTRIC END SUPPORTS PROJECTING IN AXIAL ALIGNMENT FROM SAID END COVERS SPACED RADIALLY INWARDLY OF SAID ANNULAR HOUSING, AN INNER TUBULAR MEMBER SUPPORTED ON SAID END SUPPORTS IN HEAT CONDUCTIVE RELATION TO THE ANNULAR HOUSING ENCLOSING A GAS-TIGHT CHAMBER, A PLURALITY OF INSULATIVE SUPPORT ELEMENTS MOUNTED IN AXIAL SPACED RELATION WITHIN THE INNER TUBULAR MEMBER, A PAIR OF SPACED ELECTRICALLY CONDUCTIVE RODS EXTENDING THROUGH SAID SUPPORT ELEMENTS WITHIN THE GAS-TIGHT CHAMBER BETWEEN THE END SUPPORTS, HEATING ELEMENTS CONNECTED TO SAID RODS BETWEEN THE SUPPORT ELEMENTS IN A PARALLEL CIRCUIT ARRANGEMENT, A FLUID HEATING MEDIUM DISPOSED WITHIN THE ANNULAR HOUSING TO A LEVER ABOVE THE INNER TUBULAR MEMBER, AND A THERMAL SENSING DEVICE MOUNTED ON ONE OF SAID END COVERS PROJECTING INTO THE ANNULAR HOUSING BELOW THE INNER TUBULAR MEMBER. 